U.S. patent number 11,088,939 [Application Number 16/166,571] was granted by the patent office on 2021-08-10 for reducing open shortest path first protocol link flap.
This patent grant is currently assigned to Juniper Networks, Inc.. The grantee listed for this patent is Juniper Networks, Inc.. Invention is credited to Abhishek Chakraborty, Shraddha Hegde, Rajesh Shetty Manur.
United States Patent |
11,088,939 |
Manur , et al. |
August 10, 2021 |
Reducing open shortest path first protocol link flap
Abstract
A first network device may determine that a link-state database
(LSDB), associated with the first network device, includes a first
link-state advertisement (LSA) instance associated with a second
network device. The first network device may determine that the
first network device has not received a second LSA instance,
associated with the second network device, that does not include
information identifying a fully adjacent link between the second
network device and the first network device. The first network
device may receive the second LSA instance associated with the
second network device and may transmit, to the second network
device, a third LSA instance, associated with the first network
device, that includes the information identifying the fully
adjacent link between the second network device and the first
network device, only after the second LSA instance is received.
Inventors: |
Manur; Rajesh Shetty
(Bangalore, IN), Hegde; Shraddha (Bangalore,
IN), Chakraborty; Abhishek (Bangalore,
IN) |
Applicant: |
Name |
City |
State |
Country |
Type |
Juniper Networks, Inc. |
Sunnyvale |
CA |
US |
|
|
Assignee: |
Juniper Networks, Inc.
(Sunnyvale, CA)
|
Family
ID: |
77179381 |
Appl.
No.: |
16/166,571 |
Filed: |
October 22, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L
45/124 (20130101) |
Current International
Class: |
H04L
12/721 (20130101); H04L 12/751 (20130101); H04L
12/801 (20130101) |
Field of
Search: |
;370/252 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Mesfin; Yemane
Assistant Examiner: Siddiquee; Intekhaab A
Attorney, Agent or Firm: Harrity & Harrity, LLP
Claims
What is claimed is:
1. A first network device, comprising: one or more memories; and
one or more processors to: determine that a first link-state
database (LSDB), associated with the first network device, includes
a first link-state advertisement (LSA) instance associated with a
second network device that is not included in a second LSDB
associated with the second network device, wherein the first LSA
instance, associated with the second network device, includes
out-of-date information based on a reboot of the second network
device, and wherein information identifying contents of the second
LSDB, associated with the second network device, is received from
the second network device based on the second network device
attempting to reestablish a fully adjacent link with the first
network device based on the reboot of the second network device;
delay, based on a determination that the first LSA instance,
associated with the second network device, includes the out-of-date
information, transmission of a second LSA instance, associated with
the first network device, that includes information identifying the
fully adjacent link between the second network device and the first
network device, wherein the determination that the first LSA
instance includes the out-of-date information is based on
identification of the contents of the second LSDB associated with
the second network device; determine that the first network device
has not received a third LSA instance, associated with the second
network device, that does not include the information identifying
the fully adjacent link between the second network device and the
first network device; generate a database description packet
including information identifying the contents of the first LSDB
associated with the first network device that does not identify the
second LSA instance associated with the first network device;
transmit, to the second network device, the database description
packet; receive the third LSA instance associated with the second
network device; and transmit, to the second network device, the
second LSA instance, associated with the first network device, that
includes the information identifying the fully adjacent link
between the second network device and the first network device,
wherein the second LSA instance, associated with the first network
device, is transmitted only after the third LSA instance,
associated with the second network device, is received.
2. The first network device of claim 1, wherein the first LSA
instance, associated with the second network device, includes the
information identifying the fully adjacent link between the second
network device and the first network device.
3. The first network device of claim 1, wherein the one or more
processors are further to: transmit, to the second network device
and based on receiving a link-state request, the first LSA instance
associated with the second network device, wherein the one or more
processors, when receiving the third LSA instance associated with
the second network device, are to: receive, based on transmitting
the first LSA instance associated with the second network device,
the third LSA instance associated with the second network
device.
4. The first network device of claim 1, wherein the one or more
processors are further to: receive, based on a reboot of the second
network device, a database description packet from the second
network device; and determine, based on receiving the database
description packet associated with the second network device, that
the first LSDB, associated with the first network device, includes
the first LSA instance associated with the second network
device.
5. The first network device of claim 1, wherein the one or more
processors are further to: receive, based on transmitting the
second LSA instance associated with the first network device, a
fourth LSA instance associated with the second network device,
wherein the fourth LSA instance, associated with the second network
device, includes the information identifying the fully adjacent
link between the second network device and the first network
device.
6. The first network device of claim 5, wherein the one or more
processors are further to: perform, based on the fourth LSA
instance associated with the second network device, one or more
shortest path first calculations for one or more routes in an open
shortest path first (OSPF) area.
7. The first network device of claim 5, wherein a first sequence
identifier, associated with the third LSA instance that is
associated with the second network device, is greater relative to a
second sequence identifier, associated with the first LSA instance
that is associated with the second network device; and wherein a
third sequence identifier, associated with the fourth LSA instance
associated with the second network device, is greater relative to
the first sequence identifier, associated with the third LSA
instance.
8. A non-transitory computer-readable medium storing instructions,
the instructions comprising: one or more instructions that, when
executed by one or more processors of a first network device, cause
the one or more processors to: determine, based on receiving a
database description packet associated with a second network
device, that a first link-state database (LSDB), associated with
the first network device, includes a first link-state advertisement
(LSA) instance associated with the second network device that is
not included in a second LSDB associated with the second network
device, wherein the first LSA instance, associated with the second
network device, includes out-of-date information, based on a reboot
of the second network device, that includes information identifying
a fully adjacent link between the first network device and the
second network device, and wherein the database description packet
identifies contents of the second LSDB associated with the second
network device; delay, based on a determination that the first LSA
instance, associated with the second network device, includes the
out-of-date information, transmission of a second LSA instance,
associated with the first network device, that includes the
information identifying the fully adjacent link between the second
network device and the first network device, wherein the
determination that the first LSA instance includes the out-of-date
information is based on identification of the contents of the
second LSDB associated with the second network device; determine
that the first network device has not received a third LSA
instance, associated with the second network device, that does not
include the information identifying the fully adjacent link between
the second network device and the first network device; generate
another database description packet including information
identifying the contents of the first LSDB associated with the
first network device that does not identify the second LSA instance
associated with the first network device; transmit, to the second
network device, the other database description packet; receive the
third LSA instance associated with the second network device; and
transmit, to the second network device, the second LSA instance,
associated with the first network device, that includes the
information identifying the fully adjacent link between the second
network device and the first network device, wherein the second LSA
instance, associated with the first network device, is transmitted
only after the third LSA instance, associated with the second
network device, is received.
9. The non-transitory computer-readable medium of claim 8, wherein
the one or more instructions, that cause the one or more processors
to determine that the first network device has not received the
third LSA instance, associated with the second network device,
cause the one or more processors to: determine that the first
network device has not received the third LSA instance, associated
with the second network device, based on determining that the
second LSDB, associated with the second network device, does not
include the first LSA instance associated with the second network
device.
10. The non-transitory computer-readable medium of claim 8, wherein
the one or more instructions, when executed by the one or more
processors, further cause the one or more processors to: receive,
based on a reboot of the second network device, the database
description packet from the second network device.
11. The non-transitory computer-readable medium of claim 8, wherein
the one or more instructions, when executed by the one or more
processors, further cause the one or more processors to: receive,
from the second network device, a link-state request for the first
LSA instance associated with the second network device; transmit,
to the second network device and based on receiving the link-state
request, the first LSA instance associated with the second network
device; and receive, based on transmitting the first LSA instance
associated with the second network device, the third LSA instance,
associated with the second network device.
12. The non-transitory computer-readable medium of claim 11,
wherein the one or more instructions, that cause the one or more
processors to receive the link-state request for the first LSA
instance associated with the second network device, cause the one
or more processors to: receive the link-state request based on
transmitting another database description packet to the second
network device.
13. The non-transitory computer-readable medium of claim 8, wherein
the one or more instructions, when executed by the one or more
processors, further cause the one or more processors to: receive,
based on transmitting the second LSA instance associated with the
first network device, a fourth LSA instance associated with the
second network device, wherein the fourth LSA instance, associated
with the second network device, includes the information
identifying the fully adjacent link between the first network
device and the second network device; and perform, based on the
fourth LSA instance associated with the second network device, one
or more shortest path first calculations for one or more routes in
an open shortest path first (OSPF) area.
14. The non-transitory computer-readable medium of claim 13,
wherein a first sequence identifier, associated with the third LSA
instance associated with the second network device, is greater
relative to a second sequence identifier, associated with the first
LSA instance associated with the second network device; and wherein
a third sequence identifier, associated with the fourth LSA
instance associated with the second network device, is greater
relative to the first sequence identifier, associated with the
third LSA instance associated with the second network device.
15. A method, comprising: determining, by a first network device,
that a first link-state database (LSDB), associated with the first
network device, includes a first link-state advertisement (LSA)
instance associated with a second network device that is not
included in a second LSDB associated with the second network
device, wherein the first LSA instance, associated with the second
network device, includes out-of-date information based on a reboot
of the second network device, and wherein information identifying
contents of the second LSDB, associated with the second network
device, is received from the second network device based on the
second network device attempting to reestablish a fully adjacent
link with the first network device based on the reboot of the
second network device; delaying, by the first network device and
based on a determination that the first LSA instance, associated
with the second network device, includes the out-of-date
information, transmission of a second LSA instance, associated with
the first network device, that includes information identifying the
fully adjacent link between the second network device and the first
network device; determining, by the first network device, that the
first network device has not received a third LSA instance,
associated with the second network device, that does not include
the information identifying a fully adjacent link between the
second network device and the first network device; generating, by
the first network device, a database description packet including
information identifying the contents of the first LSDB associated
with the first network device that does not identify the second LSA
instance associated with the first network device; transmitting, by
the first network device and to the second network device, the
database description packet; wherein the determination that the
first LSA instance includes the out-of-date information is based on
identifying contents of a second LSDB associated with the second
network device; receiving, at the first network device, the third
LSA instance associated with a third network device; transmitting,
by the first network device and to the second network device, the
second LSA instance, associated with the first network device, that
includes the information identifying the fully adjacent link
between the second network device and the first network device,
wherein the second LSA instance, associated with the first network
device, is transmitted only after the third LSA instance,
associated with the third network device, is received; and
receiving, at the first network device and based on transmitting
the second LSA instance associated with the first network device, a
fourth LSA instance, associated with the second network device,
that includes the information identifying the fully adjacent link
between the second network device and the first network device.
16. The method of claim 15, further comprising: performing, based
on the fourth LSA instance associated with the second network
device, one or more shortest path first calculations for one or
more routes in an open shortest path first (OSPF) area.
17. The method of claim 15, wherein a first sequence identifier,
associated with the third LSA instance that is associated with the
second network device, is greater relative to a second sequence
identifier, associated with the first LSA instance that is
associated with the second network device; and wherein a third
sequence identifier, associated with the fourth LSA instance that
is associated with the second network device, is greater relative
to the first sequence identifier, associated with the third LSA
instance that is associated with the second network device.
18. The method of claim 15, further comprising: receiving, based on
a reboot of the second network device, a database description
packet from the second network device; and determining, based on
receiving the database description packet associated with the
second network device, that the first LSDB, associated with the
first network device, includes the first LSA instance associated
with the second network device.
19. The method of claim 15, further comprising: receiving, based on
a reboot of the second network device, a database description
packet from the second network device; transmitting, based on
receiving the database description packet, another database
description packet to the second network device; receiving, based
on transmitting the other database description packet to the second
network device, a link-state request for the first LSA instance
associated with the second network device; and transmitting, based
on receiving the link-state request, the first LSA instance to the
second network device, wherein receiving the third LSA instance
associated with the second network device comprises: receiving the
third LSA instance, associated with the second network device,
based on transmitting the first LSA instance to the second network
device.
20. The method of claim 15, wherein the first LSA instance,
associated with the second network device, includes the information
identifying the fully adjacent link between the first network
device and the second network device.
Description
BACKGROUND
The open shortest path first (OSPF) protocol is a link-state
routing protocol. A network device may use the OSPF protocol to
calculate one or more shortest routes in a network for routing
and/or forwarding packets in the network.
SUMMARY
According to some implementations, a first network device may
include one or more memories, and one or more processors to
determine that a link-state database (LSDB), associated with the
first network device, includes a first link-state advertisement
(LSA) instance associated with a second network device. The one or
more processors may determine that the first network device has not
received a second LSA instance, associated with the second network
device, that does not include information identifying a fully
adjacent link between the second network device and the first
network device. The one or more processors may receive the second
LSA instance associated with the second network device. The one or
more processor may transmit, to the second network device, a third
LSA instance, associated with the first network device, that
includes the information identifying the fully adjacent link
between the second network device and the first network device,
wherein the third LSA instance is transmitted only after the second
LSA instance is received.
According to some implementations, a non-transitory
computer-readable medium may store instructions that include one or
more instructions that, when executed by one or more processors of
a device, cause the one or more processors to determine, based on
receiving a database description packet associated with a second
network device, that a link-state database (LSDB), associated with
the first network device, includes a first link-state advertisement
(LSA) instance associated with the second network device, wherein
the first LSA instance includes information identifying a fully
adjacent link between the first network device and the second
network device. The one or more instructions may cause the one or
more processors to determine that the first network device has not
received a second LSA instance, associated with the second network
device, that does not include the information identifying the fully
adjacent link between the second network device and the first
network device. The one or more instructions may cause the one or
more processors to receive the second LSA instance associated with
the second network device. The one or more instructions may cause
the one or more processors to transmit, to the second network
device, a third LSA instance, associated with the first network
device, that includes the information identifying the fully
adjacent link between the second network device and the first
network device, wherein the third LSA instance is transmitted only
after the second LSA instance is received.
According to some implementations, a method may include
determining, by a first network device, that a link-state database
(LSDB), associated with the first network device, includes a first
link-state advertisement (LSA) instance associated with a second
network device. The method may include determining, by the first
network device, that the first network device has not received a
second LSA instance, associated with the second network device,
that does not include information identifying a fully adjacent link
between the second network device and the first network device. The
method may include receiving, at the first network device, the
second LSA instance associated with the second network device. The
method may include transmitting, by the first network device and to
the second network device, a third LSA instance, associated with
the first network device, that includes the information identifying
the fully adjacent link between the second network device and the
first network device, wherein the third LSA instance is transmitted
only after the second LSA instance is received. The method may
include receiving, at the first network device and based on
transmitting the third LSA instance associated with the first
network device, a fourth LSA instance, associated with the second
network device, that includes the information identifying the fully
adjacent link between the second network device and the first
network device.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A-1C are diagrams of an example implementation described
herein.
FIG. 2 is a diagram of an example environment in which systems
and/or methods, described herein, may be implemented.
FIG. 3 is a diagram of example components of one or more devices of
FIG. 2.
FIG. 4 is a flow chart of an example process for reducing open
shortest path first protocol link flap.
FIG. 5 is a flow chart of an example process for reducing open
shortest path first protocol link flap.
FIG. 6 is a flow chart of an example process for reducing open
shortest path first protocol link flap.
DETAILED DESCRIPTION
The following detailed description of example implementations
refers to the accompanying drawings. The same reference numbers in
different drawings may identify the same or similar elements.
In some cases, an OSPF network may include one or more sub-domains,
which may be referred to as OSPF areas. A first network device and
a second network device that are neighbors in an OSPF area may form
a full adjacency. A full adjacency may include a two-way (or
bidirectional) adjacency between the first network device and the
second network device (e.g., the first network may form a first
adjacency with the second network device and the second network
device may form a second adjacency with the first network
device).
To form a full adjacency, the first network device and the second
network device may exchange one or more database description
packets. For example, the first network device may transmit a first
database description packet to the second network device, and the
second network device may transmit a second database description
packet to the first network device. The first database description
packet, associated with the first network device, may include
information specifying the contents of a first link-state database
(LSDB) associated with the first network device. Similarly, the
second database description packet, associated with the second
network device, may include information specifying the contents of
a second LSDB associated with the second network device.
The contents of an LSDB may include information identifying one or
more link-state advertisement (LSA) instances associated with the
network devices included in the OSPF area. An LSA, associated with
a particular network device, may include information identifying
one or more links that are associated with the particular network
device. For example, an LSA, associated with a particular network
device, may include information identifying a first link associated
with the particular network device, may include information
identifying a link type associated with the first link (e.g., a
point-to-point link, a virtual link, and/or the like), and/or may
include information identifying another network device to which the
particular network device is communicatively connected via the
first link (e.g., an address associated with the other network
device, a port identifier associated with the other network device,
an interface associated with the other network device, and/or the
like).
In some cases, the contents of the LSDB associated with the first
network device, and the contents of the LSDB associated with the
second network device, may differ. In such cases, the first network
device and the second network device may synchronize the respective
LSDBs. To do so, the first network device may transmit, to the
second network device, a link-state request packet, that includes a
request for one or more LSA instances, included in the LSDB
associated with the second network device, that are not included in
the LSDB associated with the first network device. The second
network device may respond to the link-state request packet by
transmitting, to the first network device, the requested one or
more LSA instances via a link-state update packet. In this way, the
first network device is able to ensure that the LSDB associated
with the first network device is up to date with the latest LSAs in
the OSPF area. The second network device and the first network
device may perform similar actions to ensure that the LSDB
associated with the second network device is also up to date with
the latest LSAs in the OSPF area.
Once the LSDB associated with the first network device and the LSDB
associated with the second network device have been synchronized,
the first network device and the second network device may
transition to a FULL state, in which the full adjacency between the
first network device and the second network device is formed. As a
result, the first network device and the second network device may
perform one or more shortest path first calculations, based on
respective LSDBs, to identify one or more routes through the OSPF
area, and may route and/or forward traffic through the OSPF area
based on the one or more identified routes.
In some cases, the first network device and the second network
device may need to reestablish full adjacency based on the first
network device and/or the second network device transitioning out
of the FULL state into a DOWN state (e.g., due to the first network
device and/or the second network device experiencing a fault, due
to a reboot of the first network device and/or the second network
device, and/or the like). For example, if the second network device
transitions into the DOWN state, the first network device may also
transition out of the FULL state into a temporary and/or
intermediate state (e.g., a one-way state, an initialize state,
and/or the like).
During reestablishment of the full adjacency, the first network
device may transition into the FULL state because the LSDB,
associated with the first network device, already includes the LSA
associated with the second network device, which includes
information identifying a fully adjacent link between the first
network device and the second network device. However, since the
second network device transitioned into the DOWN state, the link
between the first network device and the second network device is
no longer in place. Accordingly, when the first network device and
the second network device exchange database description packets,
the second network device may identify the LSA instance, associated
with the second network device, identified in the database
description packet transmitted by the first network device, may
determine that the LSDB associated with the second network device
does not include the LSA instance associated with the second
network device, and may accordingly transmit, to the first network
device, a link-state request packet that includes a request for the
LSA instance associated with the second network device. The second
network device may receive the LSA instance associated with the
second network device, and may determine that the LSA instance,
associated with the second network device, includes the information
identifying the fully adjacent link between the first network
device and the second network device, and may transmit, to the
first network device, an updated LSA instance associated with the
second network device. The updated LSA instance associated with the
second network device may not include the information identifying
the fully adjacent link between the first network device and the
second network device.
The first network device may receive the updated LSA instance
associated with the second network device, may determine that a
sequence identifier (e.g., a sequence value and/or the like),
identified in the updated LSA instance, indicates that the updated
LSA instance is more recent relative to the LSA instance,
associated with the second network device, identified in the LSDB
associated with the first network device, and accordingly may
transition out of the FULL state and into a LOADING state (e.g., an
OSPF state in which the first network device is to synchronize the
LSDB associated with the first network device), so that the first
network device can update the LSDB, associated with the first
network device, to include the updated LSA instance associated with
the second network device. The first network device may transition
back into the FULL state once the first network device and the
second network device complete LSDB synchronization.
The repeated transition of the first network device in and out of
the FULL state may be referred to as a link flap. The link flap may
cause other network devices in the OSPF area to repeatedly perform
shortest path first calculations (e.g., based on the first network
device being available in the OSPF area and based on the first
network device being unavailable in the OSPF area), which causes an
increased consumption of networking resources, processing
resources, and/or memory resources to perform the repeated shortest
past first calculations. Moreover, when the first network device
transitions from the FULL state to the LOADING state, the first
network device drops network traffic during the transition, which
decreases the availability of the first network device, decreases
the reliability of the first network device, and causes the other
network devices in the OSPF area to consume additional networking
resources, processing resources, and/or memory resources to
retransmit the dropped traffic. In addition, the link flap may
cause other protocols, executing on the first network device and
the second network device, that rely on OSPF protocol (e.g., border
gateway protocol (BGP), virtual router redundancy protocol (VRRP),
and/or the like) to also experience interruptions, which causes
further churn of network resources in the OSPF area.
Some implementations described herein provide a network device that
is capable of reducing and/or preventing link flap in an OSPF area.
The network device may determine that a link-state database (LSDB),
associated with the network device, includes a first link-state
advertisement (LSA) instance associated with another network
device. The network device may determine that the first network
device has not received a second LSA instance, associated with the
other network device, that does not include information identifying
a fully adjacent link between the other network device and the
network device. The network device may receive the second LSA
instance associated with the other network device and may transmit,
to the other network device, a third LSA instance, associated with
the network device, that includes the information identifying the
fully adjacent link between the other network device and the
network device, only after the second LSA instance is received.
In this way, the first network device delays advertising full
adjacency in the OSPF area until after receiving an updated LSA
instance from the second network device. This reduces and/or
prevents link flap (e.g., the repeated transition of the first
network device in and out of the FULL state), which prevents other
network devices in the OSPF area from repeatedly performing
shortest path first calculations, which in turn prevents the
consumption of networking resources, processing resources, and/or
memory resources that would have otherwise been expended on
performing repeated shortest past first calculations due to a
reboot of the second network device. Moreover, this reduces the
amount of traffic that is dropped at the first network device due
to link flap, which increases the availability of the first network
device, increases the reliability of the first network device, and
reduces and/or prevents other network devices in the OSPF area from
consuming additional networking resources, processing resources,
and/or memory resources that would have otherwise been expended on
retransmitting dropped traffic. In addition, this reduces and/or
prevents link flap from causing other protocols, executing on the
first network device and the second network device, that rely on
OSPF protocol (e.g., border gateway protocol (BGP), virtual router
redundancy protocol (VRRP), and/or the like) from experiencing
interruptions, which reduces churn of network resources in the OSPF
area.
FIGS. 1A-1C are diagrams of an example implementation 100 described
herein. As shown in FIGS. 1A-1C, example implementation 100 may
include a plurality of network devices, such as network device 1,
network device 2, and/or the like. Each of the plurality of network
devices may include one or more types of network devices, such as a
router, a gateway, a switch, a bridge, a wireless access point, a
base station, and/or the like. In some implementations, network
device 1 and network device 2 may be included in the same OSPF
area. The OSPF area may be included in a network, such as a
cellular network, a local area network (LAN), a core network, an
access network, a wide area network (WAN) such as the Internet, a
cloud network, and/or the like.
In example implementation 100, network device 1 and network device
2 may be communicatively connected via a fully adjacent link.
Network device 2 may experience a fault, may receive an
instruction, and/or the like, and may reboot or reset as a result.
The reboot of network device 2 may cause network device 1 to
transition to a temporary and/or intermediate state (e.g., a
one-way state), and may cause network device 2 to transition to a
DOWN state. Accordingly, network device 1 and network device 2 may
perform one or more actions to reestablish the fully adjacent
link.
As shown in FIG. 1A, and by reference number 102, to reestablish
the fully adjacent link, network device 2 may transmit a first
database description packet to network device 1, and network device
1 may transmit a second database description packet to network
device 2. The first database description packet may include
information identifying the contents of an LSDB associated with the
network device 2. Since network device 2 has been rebooted and is
in the DOWN state, the LSDB associated with the network device 2
may not include any LSAs.
Network device 1 may receive the first data description packet, may
analyze the information identifying the contents of the LSDB
associated with the network device 2, and may determine, based on
the contents of the LSDB associated with the network device 2, that
an LSDB associated with network device 1 includes a first LSA
instance, associated with network device 2, that is not included in
the LSDB associated with the network device 2. Network device 2 may
determine that, since the first LSA instance is included in the
LSDB associated with network device 1 and is not included in the
LSDB associated with network device 2, that the first LSA instance
is out of date and no longer the latest instance of network device
2's LSA.
Accordingly, and as shown by reference number 104, network device 1
may determine to not transition to the FULL state, and to not
transmit, to network device 2 (and/or other network devices in the
OSPF area) a second LSA associated with network device 1, until
only after network device 1 receives a third LSA instance (e.g., an
updated LSA instance) associated with network device 2. In this
way, network device 1 does not prematurely transition to the FULL
state, and does not prematurely advertise a fully adjacent link
between network device 1 and network device 2, until network device
2 has flooded (e.g., multicasted, broadcasted, and/or the like) an
updated LSA instance in the OSPF area, which reduces and/or
prevents link flap of the link between network device 1 and network
device 2.
Based on the above description, network device 1 may generate the
second database description packet such that the information
identifying the contents of the LSDB associated with the network
device 1 does not include the instance of the second LSA associated
with network device 1. Network device 2 may receive the second
database description packet, and may determine, based on the
information identifying the contents of the LSDB associated with
the network device 1, that the LSDB associated with network device
2 does not include the first LSA instance associated with network
device 2. Accordingly, and as shown by reference number 106,
network device 2 may transmit, to network device 1, a link-state
request packet that includes a request for the first LSA instance
associated with network device 2.
As shown in FIG. 1B, network device 1 may receive the link-state
request packet, and may identify the request for the first LSA
instance associated with network device 2. As shown by reference
number 108, network device 1 may locate, based on identifying the
request for the first LSA instance associated with network device
2, the first LSA instance in the LSDB associated with network
device 1, may generate a link-state update packet, may incorporate
the first LSA instance into the link-state update packet, and may
transmit the link-state update packet to network device 2.
Network device 2 may receive the link-state update packet and may
identify the first LSA instance associated with network device 2.
Network device 2 may analyze the first LSA instance and determine
that the first LSA instance includes information identifying a
fully adjacent link between network device 1 and network device 2.
Since network device 2 has been rebooted, and the fully adjacent
link between network device 1 and network device 2 has not yet been
reestablished, network device 2 may determine that the first LSA
instance includes incorrect and/or out-of-date information.
Accordingly, and as shown by reference number 110, network device 2
may generate the third LSA instance (e.g., the updated LSA
instance) associated with network device 2, such that the third LSA
instance does not include the information identifying the fully
adjacent link between network device 1 and network device 2, and
may transmit the third LSA instance to network device 1.
As shown in FIG. 1C, and by reference number 112, network device 1
may receive the third LSA instance associated with network device
2, may determine that the third LSA instance is now the latest LSA
instance of network device 2, and accordingly may transmit, to
network device 2, the second LSA instance associated with network
device 1. Network device 1 may determine that the third LSA
instance is the latest LSA instance associated with network device
2 based on the sequence identifier associated with the third LSA
instance. For example, network device 1 may determine that the
sequence identifier, associated with the third LSA instance,
indicates that the third LSA instance is newer, more recent, and/or
the like, relative to the first LSA instance. As an example,
network device 1 may determine that the sequence identifier,
associated with the third LSA instance, specifies a value that is
greater relative to a value specified by the sequence identifier
associated with the first LSA instance.
Network device 1 may determine to transmit the second LSA instance,
associated with network device 1, based on determining that the
third LSA instance is the latest LSA instance associated with
network device 2. As described above, the second LSA instance,
associated with network device 1, may include information
specifying a fully adjacent link between network device 1 and
network device 2. In this way, network device 1 delays
transmitting, in the OSPF area, information specifying that a fully
adjacent link exists between network device 1 and network device 2
until the latest LSA instance, associated with network device 2, is
available in the OSPF area, which reduces and/or prevents link flap
of the link between network device 1 and network device 2.
As further shown in FIG. 1C, and as shown by reference number 114,
after establishing the fully adjacent link between network device 1
and network device 2, network device 2 may transmit another LSA
instance (e.g., a fourth LSA instance) that includes information
that specifies the fully adjacent link between network device 1 and
network device 2. In this way, the fourth LSA instance, associated
with network device 2, becomes the latest LSA instance associated
with network device 2. Network device 1 may determine that the
fourth LSA instance is the latest LSA instance associated with
network device 2 based on the sequence identifier associated with
the fourth LSA instance. For example, network device 1 may
determine that the sequence identifier, associated with the fourth
LSA instance, indicates that the fourth LSA instance is newer, more
recent, and/or the like, relative to the third LSA instance. As an
example, network device 1 may determine that the sequence
identifier, associated with the fourth LSA instance, specifies a
value that is greater relative to a value specified by the sequence
identifier associated with the third LSA instance. In some
implementations, network device 1 may store the fourth LSA instance
in the LSDB associated with network device 1, and network device 2
may store the fourth LSA instance in the LSDB associated with
network device 2.
As further shown in FIG. 1C, and as shown by reference number 116,
once the fully adjacent link between network device 1 and network
device 2 has been established, network device 1 and network device
2 may transition back into the FULL state, and may perform SPF
calculations based on the information included in the respective
LSDBs, and may forward traffic in the OSPF area based on the SPF
calculations.
In this way, network device 1 delays advertising full adjacency in
the OSPF area until after receiving an updated LSA instance from
network device 2. This reduces and/or prevents link flap (e.g., the
repeated transition of network device 1 in and out of the FULL
state), which prevents other network devices in the OSPF area from
repeatedly performing shortest path first calculations, which in
turn reduces the consumption of networking resources, processing
resources, and/or memory resources that would have otherwise been
expended on performing repeated shortest past first calculations
due to a reboot of network device 2. Moreover, this reduces the
amount of traffic that is dropped at network device 1 due to link
flap, which increases the availability of network device 1,
increases the reliability of network device 1, and prevents other
network devices in the OSPF area from consuming additional
networking resources, processing resources, and/or memory resources
that would have otherwise been expended on retransmitting the
dropped traffic. In addition, this reduces and/or prevents link
flap from causing other protocols, executing on the first network
device and the second network device, that rely on OSPF protocol
(e.g., border gateway protocol (BGP), virtual router redundancy
protocol (VRRP), and/or the like) from experiencing interruptions,
which reduces churn of network resources in the OSPF area.
As indicated above, FIGS. 1A-1C are provided merely as an example.
Other examples may differ from what was described with regard to
FIGS. 1A-1C.
FIG. 2 is a diagram of an example environment 200 in which systems
and/or methods, described herein, may be implemented. As shown in
FIG. 2, environment 200 may include one or more network devices
210-1 through 210-n (n.gtoreq.1) (hereinafter referred to
collectively as "network devices 210," and individually as "network
device 210") and a network 220. Devices of environment 200 may
interconnect via wired connections, wireless connections, or a
combination of wired and wireless connections. In some
implementations, network devices 210 may be included in an OSPF
area.
Network device 210 includes one or more devices capable of
receiving, providing, storing, generating, and/or processing
information associated with reducing and/or preventing open
shortest path first protocol link flapping. In some
implementations, network device 210 may include a firewall, a
router, a gateway, a switch, a bridge, a wireless access point, a
base station (e.g., eNodeB, NodeB, gNodeB, and/or the like), and/or
the like. In some implementations, network device 210 may be
implemented as a physical device within a housing, such as a
chassis. In some implementations, network device 210 may be a
virtual device implemented by one or more computer devices of a
cloud computing environment or a data center.
In some implementations, a network device 210 may be a neighbor of
a neighboring network device 210 in the OSPF area. In some
implementations, a network device 210 may establish a fully
adjacent link with a neighboring network device 210 in the OSPF
area. In some implementations, a network device 210 may reboot, and
the network device 210 and a neighboring network device 210 may
reestablish a fully adjacent link based on the reboot.
In some implementations, during reestablishment of the fully
adjacent link, network devices 210 may exchange database
description packets, may exchange one or more link-state request
packets and/or link-state update packets to synchronize respective
LSDBs, and may transition into a FULL state once the respective
LSDBs have been synchronized. In some implementations, during
synchronization of LSDBs, the rebooting network device 210 may
transmit a database description packet to the non-rebooting network
device 210, and the non-rebooting network device 210 may determine
that the LSDB of the non-rebooting network device 210 includes an
LSA instance associated with the rebooting network device 210.
Accordingly, the non-rebooting network device 210 may determine
that the LSA instance is old, out of date, and/or not the latest
LSA instance associated with the rebooting network device 210, and
accordingly may determine to not transmit, to the rebooting network
device 210, an LSA instance, associated with the non-rebooting
network device 210, that includes information specifying a fully
adjacent link between network devices 210 until after the rebooting
network device 210 provides an updated and/or latest LSA instance
associated with the rebooting network device 210.
Network 220 includes one or more wired and/or wireless networks.
For example, network 220 may include a cellular network (e.g., a
long-term evolution (LTE) network, a code division multiple access
(CDMA) network, a 3G network, a 4G network, a 5G network, another
type of cellular network, etc.), a public land mobile network
(PLMN), a LAN, a WAN, a metropolitan area network (MAN), a
telephone network (e.g., a public switched telephone network
(PSTN)), a private network, an ad hoc network, an intranet, the
Internet, a fiber optic-based network, a cloud computing network,
or the like, and/or a combination of these or other types of
networks.
The number and arrangement of devices and networks shown in FIG. 2
are provided as an example. In practice, there may be additional
devices and/or networks, fewer devices and/or networks, different
devices and/or networks, or differently arranged devices and/or
networks than those shown in FIG. 2. Furthermore, two or more
devices shown in FIG. 2 may be implemented within a single device,
or a single device shown in FIG. 2 may be implemented as multiple,
distributed devices. Additionally, or alternatively, a set of
devices (e.g., one or more devices) of environment 200 may perform
one or more functions described as being performed by another set
of devices of environment 200.
FIG. 3 is a diagram of example components of a device 300. Device
300 may correspond to one or more of network devices 210. In some
implementations, one or more of network devices 210 may include one
or more devices 300 and/or one or more components of device 300. As
shown in FIG. 3, device 300 may include one or more input
components 305-1 through 305-B (B.gtoreq.1) (hereinafter referred
to collectively as "input components 305," and individually as
"input component 305"), a switching component 310, one or more
output components 315-1 through 315-C (C.gtoreq.1) (hereinafter
referred to collectively as "output components 315," and
individually as "output component 315"), and a controller 320.
Input component 305 may be points of attachment for physical links
and may be points of entry for incoming traffic, such as packets.
Input component 305 may process incoming traffic, such as by
performing data link layer encapsulation or decapsulation. In some
implementations, input component 305 may send and/or receive
packets. In some implementations, input component 305 may include
an input line card that includes one or more packet processing
components (e.g., in the form of integrated circuits), such as one
or more interface cards (IFCs), packet forwarding components, line
card controller components, input ports, processors, memories,
and/or input queues. In some implementations, device 300 may
include one or more input components 305.
Switching component 310 may interconnect input components 305 with
output components 315. In some implementations, switching component
310 may be implemented via one or more crossbars, via busses,
and/or with shared memories. The shared memories may act as
temporary buffers to store packets from input components 305 before
the packets are eventually scheduled for delivery to output
components 315. In some implementations, switching component 310
may enable input components 305, output components 315, and/or
controller 320 to communicate.
Output component 315 may store packets and may schedule packets for
transmission on output physical links. Output component 315 may
support data link layer encapsulation or decapsulation, and/or a
variety of higher-level protocols. In some implementations, output
component 315 may send packets and/or receive packets. In some
implementations, output component 315 may include an output line
card that includes one or more packet processing components (e.g.,
in the form of integrated circuits), such as one or more IFCs,
packet forwarding components, line card controller components,
output ports, processors, memories, and/or output queues. In some
implementations, device 300 may include one or more output
components 315. In some implementations, input component 305 and
output component 315 may be implemented by the same set of
components (e.g., an input/output component may be a combination of
input component 305 and output component 315).
Controller 320 includes a processor in the form of, for example, a
central processing unit (CPU), a graphics processing unit (GPU), an
accelerated processing unit (APU), a microprocessor, a
microcontroller, a digital signal processor (DSP), a
field-programmable gate array (FPGA), an application-specific
integrated circuit (ASIC), and/or another type of processor. The
processor is implemented in hardware, firmware, or a combination of
hardware and software. In some implementations, controller 320 may
include one or more processors that may be programmed to perform a
function.
In some implementations, controller 320 may include a random access
memory (RAM), a read only memory (ROM), and/or another type of
dynamic or static storage device (e.g., a flash memory, a magnetic
memory, an optical memory, etc.) that stores information and/or
instructions for use by controller 320.
In some implementations, controller 320 may communicate with other
devices, networks, and/or systems connected to device 300 to
exchange information regarding network topology. Controller 320 may
create routing tables based on the network topology information,
create forwarding tables based on the routing tables, and forward
the forwarding tables to input components 305 and/or output
components 315. Input components 305 and/or output components 315
may use the forwarding tables to perform route lookups for incoming
and/or outgoing packets.
Controller 320 may perform one or more processes described herein.
Controller 320 may perform these processes based on executing
software instructions stored by a non-transitory computer-readable
medium. A computer-readable medium is defined herein as a
non-transitory memory device. A memory device includes memory space
within a single physical storage device or memory space spread
across multiple physical storage devices.
Software instructions may be read into a memory and/or storage
component associated with controller 320 from another
computer-readable medium or from another device via a communication
interface. When executed, software instructions stored in a memory
and/or storage component associated with controller 320 may cause
controller 320 to perform one or more processes described herein.
Additionally, or alternatively, hardwired circuitry may be used in
place of or in combination with software instructions to perform
one or more processes described herein. Thus, implementations
described herein are not limited to any specific combination of
hardware circuitry and software.
The number and arrangement of components shown in FIG. 3 are
provided as an example. In practice, device 300 may include
additional components, fewer components, different components, or
differently arranged components than those shown in FIG. 3.
Additionally, or alternatively, a set of components (e.g., one or
more components) of device 300 may perform one or more functions
described as being performed by another set of components of device
300.
FIG. 4 is a flow chart of an example process 400 for reducing open
shortest path first protocol link flap. In some implementations,
one or more process blocks of FIG. 4 may be performed by a first
network device (e.g., network device 210). In some implementations,
one or more process blocks of FIG. 4 may be performed by another
device or a group of devices separate from or including the first
network device, such as one or more other network devices.
As shown in FIG. 4, process 400 may include determining that a
link-state database (LSDB), associated with the first network
device, includes a first link-state advertisement (LSA) instance
associated with a second network device (block 410). For example,
the first network device (e.g., using input component 305,
switching component 310, output component 315, controller 320,
and/or the like) may determine that a link-state database (LSDB),
associated with the first network device, includes a first
link-state advertisement (LSA) instance associated with a second
network device, as described above in connection with FIGS.
1A-1C.
As further shown in FIG. 4, process 400 may include determining
that the first network device has not received a second LSA
instance, associated with the second network device, that does not
include information identifying a fully adjacent link between the
second network device and the first network device (block 420). For
example, the first network device (e.g., using input component 305,
switching component 310, output component 315, controller 320,
and/or the like) may determine that the first network device has
not received a second LSA instance, associated with the second
network device, that does not include information identifying a
fully adjacent link between the second network device and the first
network device, as described above in connection with FIGS.
1A-1C.
As further shown in FIG. 4, process 400 may include receiving the
second LSA instance associated with the second network device
(block 430). For example, the first network device (e.g., using
input component 305, switching component 310, output component 315,
controller 320, and/or the like) may receive the second LSA
instance associated with the second network device, as described
above in connection with FIGS. 1A-1C.
As further shown in FIG. 4, process 400 may include transmitting,
to the second network device, a third LSA instance, associated with
the first network device, that includes the information identifying
the fully adjacent link between the second network device and the
first network device, wherein the third LSA instance is transmitted
only after the second LSA instance is received (block 440). For
example, the first network device (e.g., using input component 305,
switching component 310, output component 315, controller 320,
and/or the like) may transmit, to the second network device, a
third LSA instance, associated with the first network device, that
includes the information identifying the fully adjacent link
between the second network device and the first network device, as
described above in connection with FIGS. 1A-1C. In some
implementations, the third LSA instance is transmitted only after
the second LSA instance is received.
Process 400 may include additional implementations, such as any
single implementation or any combination of implementations
described below and/or in connection with one or more other
processes described elsewhere herein.
In some implementations, the first LSA instance, associated with
the second network device, includes the information identifying the
fully adjacent link between the second network device and the first
network device. In some implementations, the first network device
may transmit, to the second network device and based on receiving a
link-state request, the first LSA instance associated with the
second network device, and, when receiving the second LSA instance
associated with the second network device, may receive, based on
transmitting the first LSA instance associated with the second
network device, the second LSA instance associated with the second
network device.
In some implementations, the first network device may receive,
based on a reboot of the second network device, a database
description packet from the second network device, and may
determine, based on receiving the database description packet
associated with the second network device, that the LSDB,
associated with the first network device, includes the first LSA
instance associated with the second network device. In some
implementations, the first network device may receive, based on
transmitting the third LSA instance associated with the first
network device, a fourth LSA instance associated with the second
network device, wherein the fourth LSA instance includes the
information identifying the fully adjacent link between the second
network device and the first network device.
In some implementations, the first network device may perform,
based on the fourth LSA instance associated with the second network
device, one or more shortest path first calculations for one or
more routes in an open shortest path first (OSPF) area. In some
implementations, a first sequence identifier, associated with the
second LSA instance that is associated with the second network
device, is greater relative to a second sequence identifier,
associated with the first LSA instance that is associated with the
second network device, and a third sequence identifier, associated
with the fourth LSA instance associated with the second network
device, is greater relative to the first sequence identifier,
associated with the second LSA instance.
Although FIG. 4 shows example blocks of process 400, in some
implementations, process 400 may include additional blocks, fewer
blocks, different blocks, or differently arranged blocks than those
depicted in FIG. 4. Additionally, or alternatively, two or more of
the blocks of process 400 may be performed in parallel.
FIG. 5 is a flow chart of an example process 500 for reducing open
shortest path first protocol link flap. In some implementations,
one or more process blocks of FIG. 5 may be performed by a first
network device (e.g., network device 210). In some implementations,
one or more process blocks of FIG. 5 may be performed by another
device or a group of devices separate from or including the first
network device, such as one or more other network devices.
As shown in FIG. 5, process 500 may include determining, based on
receiving a database description packet associated with a second
network device, that a link-state database (LSDB), associated with
the first network device, includes a first link-state advertisement
(LSA) instance associated with the second network device, wherein
the first LSA instance includes information identifying a fully
adjacent link between the first network device and the second
network device (block 510). For example, the first network device
(e.g., using input component 305, switching component 310, output
component 315, controller 320, and/or the like) may determine,
based on receiving a database description packet associated with a
second network device, that a link-state database (LSDB),
associated with the first network device, includes a first
link-state advertisement (LSA) instance associated with the second
network device, as described above in connection with FIGS. 1A-1C.
In some implementations, the first LSA instance includes
information identifying a fully adjacent link between the first
network device and the second network device.
As shown in FIG. 5, process 500 may include determining that the
first network device has not received a second LSA instance,
associated with the second network device, that does not include
the information identifying the fully adjacent link between the
second network device and the first network device (block 520). For
example, the first network device (e.g., using input component 305,
switching component 310, output component 315, controller 320,
and/or the like) may determine that the first network device has
not received a second LSA instance, associated with the second
network device, that does not include the information identifying
the fully adjacent link between the second network device and the
first network device, as described above in connection with FIGS.
1A-1C.
As shown in FIG. 5, process 500 may include receiving the second
LSA instance associated with the second network device (block 530).
For example, the first network device (e.g., using input component
305, switching component 310, output component 315, controller 320,
and/or the like) may receive the second LSA instance associated
with the second network device, as described above in connection
with FIGS. 1A-1C.
As shown in FIG. 5, process 500 may include transmitting, to the
second network device, a third LSA instance, associated with the
first network device, that includes the information identifying the
fully adjacent link between the second network device and the first
network device, wherein the third LSA instance is transmitted only
after the second LSA instance is received (block 540). For example,
the first network device (e.g., using input component 305,
switching component 310, output component 315, controller 320,
and/or the like) may transmit, to the second network device, a
third LSA instance, associated with the first network device, that
includes the information identifying the fully adjacent link
between the second network device and the first network device, as
described above in connection with FIGS. 1A-1C. In some
implementations, the third LSA instance is transmitted only after
the second LSA instance is received.
Process 500 may include additional implementations, such as any
single implementation or any combination of implementations
described below and/or in connection with one or more other
processes described elsewhere herein.
In some implementations, when determining that the first network
device has not received the second LSA instance, the first network
device may determine that the first network device has not received
the second LSA instance based on determining that another LSDB,
associated with the second network device, does not include the
first LSA instance associated with the second network device. In
some implementations, the first network device may receive, based
on a reboot of the second network device, the database description
packet from the second network device.
In some implementations, the first network device may receive, from
the second network device, a link-state request for the first LSA
instance associated with the second network device, may transmit,
to the second network device and based on receiving the link-state
request, the first LSA instance associated with the second network
device, and may receive, based on transmitting the first LSA
instance associated with the second network device, the second LSA
instance associated with the second network device.
In some implementations, when receiving the link-state request for
the first LSA instance associated with the second network device,
the first network device may receive the link-state request based
on transmitting another database description packet to the second
network device. In some implementations, the first network device
may receive, based on transmitting the third LSA instance
associated with the first network device, a fourth LSA instance
associated with the second network device, wherein the fourth LSA
instance includes the information identifying the fully adjacent
link between the first network device and the second network
device, and may perform, based on the fourth LSA instance
associated with the second network device, one or more shortest
path first calculations for one or more routes in an open shortest
path first (OSPF) area.
In some implementations, a first sequence identifier, associated
with the second LSA instance associated with the second network
device, is greater relative to a second sequence identifier,
associated with the first LSA instance associated with the second
network device, and a third sequence identifier, associated with
the fourth LSA instance associated with the second network device,
is greater relative to the first sequence identifier, associated
with the second LSA instance associated with the second network
device.
Although FIG. 5 shows example blocks of process 500, in some
implementations, process 500 may include additional blocks, fewer
blocks, different blocks, or differently arranged blocks than those
depicted in FIG. 5. Additionally, or alternatively, two or more of
the blocks of process 500 may be performed in parallel.
FIG. 6 is a flow chart of an example process 600 for reducing open
shortest path first protocol link flap. In some implementations,
one or more process blocks of FIG. 6 may be performed by a first
network device (e.g., network device 210). In some implementations,
one or more process blocks of FIG. 6 may be performed by another
device or a group of devices separate from or including the first
network device, such as one or more other network devices.
As shown in FIG. 6, process 600 may include determining that a
link-state database (LSDB), associated with the first network
device, includes a first link-state advertisement (LSA) instance
associated with a second network device (block 610). For example,
the first network device (e.g., using input component 305,
switching component 310, output component 315, controller 320,
and/or the like) may determine that a link-state database (LSDB),
associated with the first network device, includes a first
link-state advertisement (LSA) instance associated with a second
network device, as described above in connection with FIGS.
1A-1C.
As shown in FIG. 6, process 600 may include determining that the
first network device has not received a second LSA instance,
associated with the second network device, that does not include
information identifying a fully adjacent link between the second
network device and the first network device (block 620). For
example, the first network device (e.g., using input component 305,
switching component 310, output component 315, controller 320,
and/or the like) may determine that the first network device has
not received a second LSA instance, associated with the second
network device, that does not include information identifying a
fully adjacent link between the second network device and the first
network device, as described above in connection with FIGS.
1A-1C.
As shown in FIG. 6, process 600 may include receiving the second
LSA instance associated with the second network device (block 630).
For example, the first network device (e.g., using input component
305, switching component 310, output component 315, controller 320,
and/or the like) may receive the second LSA instance associated
with the second network device, as described above in connection
with FIGS. 1A-1C.
As shown in FIG. 6, process 600 may include transmitting, to the
second network device, a third LSA instance, associated with the
first network device, that includes the information identifying the
fully adjacent link between the second network device and the first
network device, wherein the third LSA instance is transmitted only
after the second LSA instance is received (block 640). For example,
the first network device (e.g., using input component 305,
switching component 310, output component 315, controller 320,
and/or the like) may transmit, to the second network device, a
third LSA instance, associated with the first network device, that
includes the information identifying the fully adjacent link
between the second network device and the first network device, as
described above in connection with FIGS. 1A-1C. In some
implementations, the third LSA instance is transmitted only after
the second LSA instance is received.
As shown in FIG. 6, process 600 may include receiving, based on
transmitting the third LSA instance associated with the first
network device, a fourth LSA instance, associated with the second
network device, that includes the information identifying the fully
adjacent link between the second network device and the first
network device (block 650). For example, the first network device
(e.g., using input component 305, switching component 310, output
component 315, controller 320, and/or the like) may receive, based
on transmitting the third LSA instance associated with the first
network device, a fourth LSA instance, associated with the second
network device, that includes the information identifying the fully
adjacent link between the second network device and the first
network device, as described above in connection with FIGS.
1A-1C.
Process 600 may include additional implementations, such as any
single implementation or any combination of implementations
described below and/or in connection with one or more other
processes described elsewhere herein.
In some implementations, the first network device may perform,
based on the fourth LSA instance associated with the second network
device, one or more shortest path first calculations for one or
more routes in an open shortest path first (OSPF) area. In some
implementations, a first sequence identifier, associated with the
second LSA instance that is associated with the second network
device, is greater relative to a second sequence identifier,
associated with the first LSA instance that is associated with the
second network device, and a third sequence identifier, associated
with the fourth LSA instance that is associated with the second
network device, is greater relative to the first sequence
identifier, associated with the second LSA instance that is
associated with the second network device.
In some implementations, the first network device may receive,
based on a reboot of the second network device, a database
description packet from the second network device, and determine,
based on receiving the database description packet associated with
the second network device, that the LSDB, associated with the first
network device, includes first the LSA instance associated with the
second network device.
In some implementations, the first network device may receive,
based on a reboot of the second network device, a database
description packet from the second network device, may transmit,
based on receiving the database description packet, another
database description packet to the second network device, may
receive, based on transmitting the other database description
packet to the second network device, a link-state request for the
first LSA instance associated with the second network device, and
may transmit, based on receiving the link-state request, the first
LSA instance to the second network device, wherein when receiving
the second LSA instance associated with the second network device,
the first network device may receive the second LSA instance based
on transmitting the first LSA instance to the second network
device.
In some implementations, the first LSA instance, associated with
the second network device, includes the information identifying the
fully adjacent link between the first network device and the second
network device.
Although FIG. 6 shows example blocks of process 600, in some
implementations, process 600 may include additional blocks, fewer
blocks, different blocks, or differently arranged blocks than those
depicted in FIG. 6. Additionally, or alternatively, two or more of
the blocks of process 600 may be performed in parallel.
As used herein, the term traffic or content may include a set of
packets. A packet may refer to a communication structure for
communicating information, such as a protocol data unit (PDU), a
network packet, a datagram, a segment, a message, a block, a cell,
a frame, a subframe, a slot, a symbol, a portion of any of the
above, and/or another type of formatted or unformatted unit of data
capable of being transmitted via a network.
The foregoing disclosure provides illustration and description, but
is not intended to be exhaustive or to limit the implementations to
the precise form disclosed. Modifications and variations may be
made in light of the above disclosure or may be acquired from
practice of the implementations.
As used herein, the term component is intended to be broadly
construed as hardware, firmware, and/or a combination of hardware
and software.
It will be apparent that systems and/or methods, described herein,
may be implemented in different forms of hardware, firmware, or a
combination of hardware and software. The actual specialized
control hardware or software code used to implement these systems
and/or methods is not limiting of the implementations. Thus, the
operation and behavior of the systems and/or methods were described
herein without reference to specific software code--it being
understood that software and hardware can be designed to implement
the systems and/or methods based on the description herein.
Even though particular combinations of features are recited in the
claims and/or disclosed in the specification, these combinations
are not intended to limit the disclosure of possible
implementations. In fact, many of these features may be combined in
ways not specifically recited in the claims and/or disclosed in the
specification. Although each dependent claim listed below may
directly depend on only one claim, the disclosure of possible
implementations includes each dependent claim in combination with
every other claim in the claim set.
No element, act, or instruction used herein should be construed as
critical or essential unless explicitly described as such. Also, as
used herein, the articles "a" and "an" are intended to include one
or more items, and may be used interchangeably with "one or more."
Furthermore, as used herein, the term "set" is intended to include
one or more items (e.g., related items, unrelated items, a
combination of related and unrelated items, etc.), and may be used
interchangeably with "one or more." Where only one item is
intended, the term "one" or similar language is used. Also, as used
herein, the terms "has," "have," "having," or the like are intended
to be open-ended terms. Further, the phrase "based on" is intended
to mean "based, at least in part, on" unless explicitly stated
otherwise.
* * * * *